Pharmaceutical compositions and methods for insulin treatment

ABSTRACT

Compositions and methods for treating a patient with insulin that combines insulin, a permeation enhancer, and a carrier that maintains an acidic pH, are disclosed.

This application is a continuation of U.S. application Ser. No.11/002,858, filed Dec. 2, 2004, and claims the priority of U.S.Provisional Application Ser. No. 60/527,728 filed on Dec. 8, 2003, thedisclosures of each of which are hereby incorporated by reference intheir entireties.

This invention relates to compositions and methods for delivery ofinsulin, and more particularly for the delivery of insulin other than byinjection, across skin, membranes of various body cavities such asocular, nasal, oral, buccal, anal, rectal, vaginal, and blood brainbarrier and like membranes.

Insulin is generally used to treat patients that suffer from diabetes.In general, insulin is delivered to a patient by injection.

U.S. Pat. No. 5,023,252 describes a composition for delivery of insulinby a route other than by injection. More particularly, such patentdescribes the use of compositions that include permeation enhancers fordelivery of insulin through skin and membranes of body cavities withoutrequiring an injection.

The present invention is directed to an improvement in such compositionsand the use thereof.

In accordance with the invention, there is provided a pharmaceuticalcomposition comprising: (A) insulin; (B) a permeation enhancer; and (C)a liquid carrier wherein the composition is at an acidic pH.

Applicant has found that when using a composition that contains acombination of insulin and permeation enhancer, improved results areobtained when the composition is at an acidic pH.

The invention further relates to treating a patient in need of insulinwith a combination of insulin, a permeation enhancer, and a liquidcarrier; the combination having an acidic pH of no greater than 4.5.Preferably the pH of the composition is no greater than 4 nor below 2.The pH is preferably at least 2.

In general, the pH of the composition is at least 2 and no greater than4.5. In a preferred embodiment, the pH is no greater than 4. A preferredrange of pH is from 2.5 to 3.8. In one preferred embodiment the pH isabout 3.

The pH of the composition may be maintained by the use of a suitablebuffer. The selection of a buffer to maintain the desired pH is deemedto be within the scope of those skilled in the art based on theteachings set forth herein. As representative examples of suitablebuffers there may be mentioned citric acid buffer, phosphate buffer, andthe like, as is in common use and also suitable for medicalformulations.

In general, the permeation enhancer that is employed is one thatenhances the permeation of the insulin composition through the membraneof a bodycavity

In general, the permeation enhancer that is employed is one thatenhances the permeation of the insulin composition through the membraneof a body cavity and in particular through the nasal mucosa.

In a composition containing an effective amount of insulin a preferredpermeation enhancer is a compound of the structure:

wherein X and Y are oxygen, sulfur or an imino group of the structure

or ═N—R with the proviso that when Y is the imino group, X is an iminogroup, and when Y is sulfur, X is sulfur or an imino group, A is a grouphaving the structure

wherein X and Y are defined above, m and n are integers having a valuefrom 1 to 20 and the sum of m+n is not greater than 25, p is an integerhaving a value of 0 or 1, q is an integer having a value of 0 or 1, r isan integer having a value of 0 or 1, and each of R, R₁, R₂, R₃, R₄, R₅and R₆ is independently hydrogen or an alkyl group having from 1 to 6carbon atoms which may be straight chained or branched provided thatonly one of R₁ to R₆ can be an alkyl group, with the proviso that whenp, q and r have a value of 0 and Y is oxygen, m+n is at least 11, andwith the further proviso that when X is an imino group, q is equal to 1,Y is oxygen, and p and r are 0, then m+n is at least 11, and saidcompound will enhance the rate of the passage of the drug across bodymembranes. Hereinafter these compounds are referred to as enhancers.When R, R₁, R₂, R₃, R₄, R₅ or R₆ is alkyl it may be methyl, ethyl,propyl, isopropyl, butyl, isobutyl, sec-butyl, amyl, hexyl, and thelike. Such permeation enhancers are described in U.S. Pat. No. 5,023,252and U.S. Pat. No. 5,731,303.

Preferably, the compounds of this invention are the cyclic lactones (thecompounds wherein both X and Y are oxygen, (q is 1 and r is 0), thecyclic diesters (the compounds wherein both X and Y are oxygen, and bothq and r are 1), and the cyclic ketones (the compounds wherein both q andr are 0 and Y is oxygen). In the cyclic diesters m+n is preferably atleast 3. In the cyclic ketones m+n is preferably from 1 1 to 15 and p ispreferably 0.

Enhancers of the above structural formula are referred to herein as“Hsieh enhancers” and are described, for example, in aforementioned U.S.Pat. No. 5,023,252 and 5,731,303 (hereinafter “Hsieh Patents”). Suchenhancers are lipophilic and are “membrane-compatible,” meaning thatthey do not cause damage to the membrane on which the composition of thepresent invention is to be applied (hereinafter “target membrane”). Suchenhancers produce also a low level of irritability or no irritability tothe target membrane and, in fact serve as an emollient.

Preferred enhancers for use in the present invention are macrocyclicenhancers. The term “macrocyclic” is used herein to refer to cycliccompounds having at least 12 carbons in the ring. Examples of preferredmacrocyclic enhancers for use in the present invention include: (A)macrocyclic ketones, for example, 3 methylcyclopentadecanone (muscone),9-cycloheptadecen-1-one (civetone), cyclohexadecanone, andcyclopentadecanone (normuscone); and (B) macrocyclic esters, forexample, pentadecalactones such as oxacyclohexadecan-2-one(cyclopentadecanolide, ω-pentadecalactone).

Oxacyclohexadecan-2-one and cyclopentadecanone are especially preferred.

Although the above are preferred permeation enhancers, one of ordinaryskill in the art would recognize that the instant teachings would alsobe applicable to other permeation enhancers. Non-limiting examples ofother permeation enhancers useful in the instant invention are thesimple long chain esters that are Generally Recognized As Safe (GRAS) inthe various pharmacopoeial compendia. These may include simplealiphatic, unsaturated or saturated (but preferably fully saturated)esters, which contain up to medium length chains. Non-limiting examplesof such esters include isopropyl myristate, isopropyl palmitate,myristyl myristate, octyl palmitate, and the like. The enhancers are ofa type that are suitable for use in a pharmaceutical composition. Theartisan of ordinary skill will also appreciate that those materials thatare incompatible with or irritating to mucous membranes should beavoided.

The enhancer is present in the composition in a concentration effectiveto enhance penetration of the insulin, to be delivered, through themembrane. Various considerations should be taken into account indetermining the amount of enhancer to use. Such considerations include,for example, the amount of flux (rate of passage through the membrane)achieved and the stability and compatibility of the components in theformulations. The enhancer is generally used in an amount of about 0.01to about 25 wt. % of the composition, more generally in an amount ofabout 0.1 to about 15 wt. % of the composition, and in preferredembodiments in an amount of about 0.5 to about 15 wt % of thecomposition.

The liquid carrier is present in the composition in a concentrationeffective to serve as a suitable vehicle for the compositions of thepresent invention. In general, the carrier is used in an amount of about40 to about 98 wt. % of the composition and in preferred embodiments inan amount of about 50 to about 98 wt. % of the composition.

The insulin compositions of the present invention are preferablydelivered as a nasal spray. In such an embodiment, the preferred liquidcarrier is water with the insulin being dispersed or dissolved in thewater in a therapeutically effective amount.

In one preferred embodiment, the permeation enhancer is emulsified inthe aqueous phase that contains the insulin. The emulsification may beeffected through the use of one or more suitable surfactants. Theselection of a suitable surfactant is deemed to be within the scope ofthose skilled in the art based on the teachings herein. Essentially anysuitable surfactant or mixture of surfactants can be used in thepractice of the present invention, including, for example, anionic,cationic, and non-ionic surfactants. Preferred surfactants are non-ionicsurfactants, with those having a hydrophilic-lipophilic balance (HLB) offrom about 7 to about 14 being particularly preferred. Examples of suchnon-ionic surfactants are PEG-60 corn glycerides, PEG-20 sorbitanmonostearate, phenoxy-poly(ethyleneoxy)ethanol, sorbitan monooleate, andthe like. Especially preferred are compendial surfactants such as thosedescribed in compendia such as the Food Chemicals Codex, NationalFormulary, U.S. Pharmacopeia, and the Code of Federal Regulations. It ispreferred that the average diameter of the droplets of the emulsion befrom about 500 mn to about 20 μm and more preferably from about 1 μm toabout 10 μm. In general the surfactant is present in an amount nogreater than about 2 wt. % of the composition and more generally nogreater than about 0.5 wt. % of the composition.

In one preferred embodiment, the emulsified or discontinuous phase thatcontains the permeation enhancer is in the form of droplets. In general,smaller droplets confer greater stability. Larger droplets may causeinstability and decrease shelf-life. In preferred embodiments thedroplet size ranges from 0.1 microns to 20 microns and preferably from0.1 microns to 5 microns.

In general compositions that contain insulin are stored in arefrigerator and such refrigeration may result in crystallization of thepermeation inhibitor. In order to inhibit or prevent suchcrystallization, in a preferred embodiment the composition includes oneor more crystallization inhibitors to inhibit the crystallization of thepermeation enhancer. Crystallization, if allowed to proceed, renders theemulsion unstable and has an adverse effect on shelf life. Preferredcrystallization inhibitors function by lowering the temperature at whichthe involved compound crystallizes. Examples of such crystallizationinhibitors include natural oils, oily substances, waxes, esters, andhydrocarbons. Examples of natural oils or oily substances includeVitamin E acetate, octyl palmitate, sesame oil, soybean oil, saffloweroil, avocado oil, palm oil, and cottonseed oil. The selection of asuitable crystallization inhibitor is deemed to be within the scope ofthose skilled in the art from the teachings herein. Preferredcrystallization inhibitors function by lowering the temperature at whichthe permeation enhancer crystallizes.

Inhibitors which are capable of lowering the temperature ofcrystallization of the involved compound to below about 25° C. areparticularly preferred, with those capable of lowering thecrystallization of the involved compound to below about 5° C. beingespecially preferred. Examples of especially preferred crystallizationinhibitors for use in inhibiting the crystallization ofoxacyclohexadecan-2-one include hexadecane, isopropyl myristate, octylpalmitate, cottonseed oil, safflower oil, and Vitamin E acetate, each ofwhich may be used in pharmaceutical preparations.

The crystallization inhibitor is present in the composition in aconcentration effective to inhibit the crystallization of the permeationenhancer. In general the crystallization inhibitor is present in anamount of about 0.001 to about 5 wt. % of the composition, moregenerally in an amount of from about 0.01 to about 2 wt % of thecomposition. In one embodiment the crystallization inhibitor is presentin an amount of from about 0.1 to about 1 wt. % of the composition. Thecrystallization inhibitor is one preferably used when the enhancer has acrystallization temperature above about 0 degrees Centigrade. Inparticular, for example, a crystallization inhibitor is preferably usedwhen the enhancer is, pentadecalactone and / or cyclohexadecanone, sincethese crystallize above room temperature.

The composition of the present invention is generally delivered througha nasal spray applicator. If intra-nasal application is desired, thecomposition may be placed in an intra-nasal spray-dosing device oratomizer and be applied by spraying it into the nostrils of a patientfor delivery to the mucous membrane of the nostrils. A sufficient amountis applied to achieve the desired systemic or localized drug levels. Foran intra-nasal spray, up to about 200 microliters is typically applied,with an application of about 50 to about 150 microliters beingpreferred. One or more nostrils may be dosed and application may occuras often as desired or as often as is necessary. In preferredembodiments, the nasal spray applicator is selected to provide dropletsof the composition of a mean size of from about 10 microns to about 200microns. More generally the droplet size is from about 30 microns toabout 100 microns.

The insulin spray composition of the invention is generally employed ina dosing regimen that is dependent on the patient being treated. Thusthe frequency of the use and the amount of the dose may vary frompatient to patient. In general, dosing is in an amount (the amountinternalized after absorption from the mucosa) of from about 3 IU toabout 15 IU and the frequency of dose is 3 to 4 times per day. As knownin the art, the treatment of a disease such as diabetes through insulintherapy varies from patient to patient, and based on known insulintherapy and the teachings herein one skilled in the art can select thedosing regimen and dosage for a particular patient or patients.

The composition of the present invention comprises insulin. The insulinis present in the composition in a therapeutically-effective amount. Ingeneral the insulin is present in an amount of about 0.01 to about 15wt. % of the composition, more generally an amount of about 0.01 toabout 10 wt. % of the composition. In one embodiment the insulin ispresent in an amount of about 0.1 to about 5 wt. % of the composition.

Although a preferred embodiment is a preformulated composition, it isalso within the scope of the present invention that a patient may betreated with the hereinabove described combination that is notpreformulated; i.e., the insulin in liquid carrier and the enhancer maybe mixed at the time of application, such as where the mixing occurs inan atomizer at the time the composition is sprayed.

The Examples illustrate preferred embodiments of the invention and arenot to be regarded as limiting.

EXAMPLE 1

Four separate aqueuos insulin emulsions of the present invention(formulations A, B, C, and D) are prepared according to the formulationsdescribed in the table below. Component CPE-215 is the Applicant'sproprietary compound and is also known as Cyclopentadecanolide; itfacilitates the migration of insulin through the nasal mucosa. InsulinFormulation for Pig Experiment Code: A B C D Reagents: % % % % Insulin0.1 1.0 1.0 1.0 CPE-215 — 2.0 2.0 2.0 Cottonseed Oil — 1.0 1.0 0.7Glycerin — — — 2.0 Sorbitan Laurate — 0.6 0.6 — (a.k.a. Crill 1; asurfactant) Polysorbate 20 — 0.7 0.7 — (a.k.a. Crillet 1; a surfactant)Pemulen TR2 — — — 0.1 H2O 99.1  94.3  93.2  93.7  TEA — — — 0.5 HCl (5N)— — 0.2 — NaOH (1N) — — 1.3 — Citric Acid 0.6 0.3 — — (1H2O) SodiumCitrate 0.2 0.1 — — (2H2O) Benzalkonium — — —  0.003 chloride 100   100    100    100    pH:  3.19  3.53  7.32  8.07

EXAMPLE 2

C-peptide blood levels can indicate whether or not a person is producinginsulin and approximately how much. Insulin is initially synthesized inthe pancreas as proinsulin. In this form the alpha and beta chains ofactive insulin are linked by a third polypeptide chain called theconnecting peptide, or C-peptide, for short. Because both insulin andC-peptide molecules are secreted, for every molecule of insulin in theblood, there is one of C-peptide. Therefore, levels of C-peptide in theblood can be measured and used as an indicator of insulin production inthose cases where exogenous insulin (from injection) is present andmixed with endogenous insulin (that produced by the body) a situationthat would make meaningless a measurement of insulin itself. TheC-peptide test can also be used to help assess if high blood glucose isdue to reduced insulin production or to reduced glucose intake by thecells. There is little or no C-peptide in the blood of type 1 diabetichumans, and C-peptide levels in type 2 diabetics can be reduced ornormal. The concentrations of C-peptide in non-diabetics are on theorder of 0.5-3.0 ng/ml.

An evaluation of the compositions of this invention was carried out invivo as described below.

Pharmacokinetics and Pharmacodynamics in Yucatan Minipigs of IntranasalCPE-215/Insulin Formulations

This study was performed in accordance with the NIH “Guide For the Careand Use of Laboratory Animals” and the Federal Animal Welfare Act, andfollowed a protocol approved by the University of New HampshireInstitutional Animal Care and Use Committee. This study's objective wasto evaluate and characterize the pharmacokinetic and pharmacodynamiceffectiveness of insulin formulations after intranasal delivery toYucatan minipigs.

Previously, it had been determined, in beagles (Hseih, 1993), thatCyclopentadecanolide facilitates the migration of insulin through thenasal mucosa. In order to verify this in minipigs, as a step towardevaluation in human volunteers, formulations were assessed for insulinblood levels and glucodynamics.

Materials, Methods, and Formulations

The formulations tested were aqueous insulin emulsions, containingpharmaceutical grade human recombinant insulin, obtained from Diosynth,Inc., a division of Akzo Nobel, Inc. These formulations varied slightlyin composition; however, each contained insulin at 1 % w/w, and CPE-215at 2% w/w. These formulations were dispensed from intranasal atomizers,developed for humans by Valois of America. Two puffs of 100 microliterseach were dispensed to pigs that had previously been cannulated with anindwelling jugular catheter. Each 100 microliter spray dispensed 1milligram, or approximately 25 IU of insulin. An extension to theactuator was used, provided also by Valois of America, the need forwhich (to deliver formulation to the absorptive surface of the vestibuleand labyrinthine turbinate region) was determined in a preliminary pilotstudy. The same actuator, dispensing 100 microliters, was used with theextension attached. These intranasally delivered doses were compared tothree units of insulin administered subcutaneously (SQ) as a positivecontrol.

Animal Protocol

Four female Yucatan miniature swine (pigs) were purchased from the UNHMiniature Swine Research Farm. During the study, the pigs were housed inan environmentally controlled research animal room (temperature 25+/−2 Cand 12 hour light/dark cycle), fed commercial research pig chow, and hadfree access to water at all times. The pigs were 21 week-old Yucatanfemales:

Pig #1, Tag 121-5; Weight at start of study: 16.8 kg; DOB Nov. 26, 2002

Pig #2, Tag 121-4; Weight at start of study: 22.3 kg; DOB Nov. 26, 2002[Note: #1 and #2 are littermates]

Pig #3, Tag 122-7; Weight at start of study: 18.3 kg; DOB Dec. 1, 2002

Pig #4, Tag 122-9; Weight at start of study: 15.5 kg; DOB Dec. 1, 2002[Note: #3 and #4 are littermates].

Catheterization Methodology

The animals were prepared for the study with the surgical implantationof a jugular catheter 4 to 6 days before the study start. After heavysedation with an intramuscular dose of xylazine and ketamine, theanimals were masked down and maintained to effect deep surgicalanesthesia with inhalation of isofluorane anesthetic and oxygen. Withthe animals in dorsal recumbency, a skin incision was made in the rightjugular furrow and followed by blunt dissection of the subcutaneous andperivascular connective tissues to expose the right jugular vein cranialto the thoracic inlet. A length of 0.050 inch bore Tygon® intravenouscatheter tubing was inserted through a small incision in the clampedvein and positioned caudally into the anterior vena cava (approximately12 to 15 cm from the jugular incision). The catheter was transfixed tothe vein and deep subcutaneous tissues suture. The jugular vein cranialto the catheter was ligated with polypropylene suture. The free end ofthe catheter was routed by blunt dissection through the subcutis to theinterscapular dorsum, pulled through a small skin incision, andtransfixed to the skin with polypropylene suture. The catheter wascapped with a syringe docking device and filled with an anti-thromboticpreparation. The antithrombotic consisted of 60% (w/v)polyvinylpyrrolidone (10,000 mw, PVP-10) and physiologic saline/sodiumheparin (50,000 units of heparin per 100 mL). The subcutis and skinincision in the jugular furrow were closed with synthetic absorbable andpolypropylene sutures, respectively. The animals were comfortablybandaged to protect the catheter and skin incision and covered with avest made for dog catheter work. Intramuscular butorphanol wasadministered as an analgesic immediately and 12 hours after surgery.

Study Design

At the time of dosing, the pigs were restrained in a cloth sling. Thepigs were afterwards free to move about their respective individual pensand were only temporarily restrained in close quarters at the front ofthe pen with a movable wooden gate at the time of blood sampling. Eachpig was dosed twice with each of the four different formulations over atwo week period with at least 18 hours between treatments. Theintranasal dosing (Formulation B, C, D) entailed dispensing 100 μL of a1 % insulin emulsion through an aerosol doser (human type intranasalactuator), once per each nostril (Total dose 50 IU), or subcutaneousdosing (Formulation A), 120 0 μL of a 0.1 % buffered sterile solutionusing a 1 cc sterile syringe (3 IU) equipped with a 22 ga. needle.Dosing intervals between pigs was timed, and was approximately fiveminutes.

Baseline venous blood specimens were collected just prior to intranasalor SQ insulin administration, and blood was thereafter sampled at 0(just before treatment), 15, 30, 45, 60, 90, 120, and 80 minutes afterapplication. Bleeding was approximately five minutes apart between pigs,the interval adjusted relative to the dosing time within one minute oftarget time. Each pig was monitored with a hand-held commercialglucometer at each blood collection time to ensure animal wellness.

The blood was collected into sodium heparinized glass tubes. The plasmawas retrieved and stored at −20° C. until analyzed for insulin,C-peptide, and glucose. There were eight days of treatment, with each ofthe four pigs treated each day. Pigs were crossed over (two successiveidentical latin squares) with each pig receiving a different treatmenteach day, according to the following schedule:

Treatment Schedule D = Day P = Pig Treatments D1 = Mar. 25, 2003 P1 =Pig 121-5 A = Subcutaneous 120 μL (3 IU) D2 = Mar. 26, 2003 P2 = Pig121-4 B = IN Form. 013-44-2 pH 3.5 D3 = Mar. 27, 2003 P3 = Pig 122-7 C =IN Form. 013-44-3 pH 7.32 D4 = Mar. 28, 2003 P4 = Pig 122-9 D = IN Form.013-45 pH 8.0 D5 = Apr. 1, 2003 D6 = Apr. 2, 2003 D7 = Apr. 3, 2003 D8 =Apr. 4, 2003

Treatment/Days Day Pig 1 Pig 2 Pig 3 Pig 4 1 A B C D 2 B C D A 3 C D A B4 D A B C 5 A B C D 6 B C D A 7 C D A B 8 D A B CSample Collection and Assay Methods

Heparinized plasma was analyzed for insulin concentration using acommercial RIA assay for insulin (Linco research, Inc.; Human InsulinSpecific RIS Kit, Cat# HI-14K). Insulin was reported in microInternational Units)/milliliter of plasma (PU/mL). C-Peptide wasanalyzed with a commercial kit specific for porcine C-Peptide (Lincoresearch, Inc.; Porcine C-Peptide RIA Kit, Cat# PCP-22K) and reported inunits of ng/mL.

Glucose was measured at the time of collection using a Glucometer(Lifescan (J&J) One Touch Fast Take™), and in the laboratory using acommercial enzymatic assay (Sigma Diagnostics, Procedure 315) and wasmeasured in mg/dL.

Deviation from Protocol

There were no deviations from protocol.

Results for Glucose

The results showed good reduction in blood glucose values, as measuredin blood by the hexokinase enzymatic method, and are historicallycommensurate for this positive control, SQ insulin; the SQ dose reacheda minimum glucose level at an average of 30 minutes Post Rx. Forintranasal Formulation B, excellent glucodynamic reduction was seen witha more rapid onset, 15 minutes or faster to trough, but of shorterduration (90-120 min.) than SQ (180 min.). Formulation C had a similarrapid onset to B, but of less magnitude. Formulation D was devoid ofappreciable glucodynamic activity. The reproducibility, both intradoseand day to day, was good (no variances of any treatment differedsignificantly, P<0.05). (See FIG. 1)

The enzymatic glucose assay correlated well with the correspondingglucometer results performed at the time of blood collection (r=0.9575;p<0.0001).

Results for Insulin

The results showed good insulin blood levels for the Formulation A, SQpositive control, with the average value peaking at 15 minutes with anaverage C_(max) of 59.85 μU/mL. (See FIG. 2).

Formulation B showed much higher blood levels than any otherformulation, peaking at 15 minutes with an average C_(max) of 182.4μU/mL. (See FIG. 2).

Formulation C showed lower blood levels than either A or B, indicatingreduced delivery of insulin at physiological pH compared with the acidicform, having a C_(max) of 64.59 μU/mL at 15 minutes. (See FIG. 2).

Formulation D showed little change over fasted baseline levels. NoC_(max) was observed. (See FIG. 2).

Results for C-Peptide

C-Peptide for fasted, untreated animals (time zero) averaged 0.35 ng/mL(n=36). The onset of action of the four treatments was similar to therespective curves obtained for the glucodynamics. Treatment B has afaster onset of depression of C-Peptide, followed by A, then C, then D.Treatment A had the longest depression of C-Peptide, approximately 3hours, whereas the other treatments had normal levels by this time,reflecting resumption of endogenous insulin production.

1. A pharmaceutical composition comprising: a therapeutically effectiveamount of insulin, a permeation enhancer, and a liquid carrier; saidcomposition being at an acidic pH, but no greater than a pH of 4.5. 2.The pharmaceutical composition of claim 1, wherein said acidic pH isfrom about 2 to about
 4. 3. The pharmaceutical composition of claim 1,wherein said acidic pH is about
 3. 4. The pharmaceutical composition ofclaim 1, wherein said acidic pH is about 3.5
 5. The pharmaceuticalcomposition of claim 1, further comprising a crystallization inhibitor.6. The pharmaceutical composition of claim 1, wherein said compositionis in the form of a solution.
 7. The pharmaceutical composition of claim1, wherein said composition is in the form of a spray solution.
 8. Thepharmaceutical composition of claim 1, wherein said permeation enhanceris a Hsieh enhancer.
 9. The pharmaceutical composition of claim 8,wherein said Hsieh enhancer is cyclopentadecalactone orcylcohexadecanone.
 10. The pharmaceutical composition of claim 1,wherein said permeation enhancer is a straight chain or branchedcompound of the saturated or unsaturated aliphatic type.
 11. Thepharmaceutical composition of claim 10, wherein said straight chain orbranched compound of the saturated or unsaturated aliphatic type isselected from the group consisting of: myristyl myristate, isopropylmyristate, octyl palmitate, and ethyl oleate.
 12. A method for treatinga patient with insulin comprising administering to a patient in need ofinsulin treatment a combination comprising: a therapeutically effectiveamount of insulin, a permeation enhancer, and a liquid carrier; saidcombination being at an acidic pH, but no greater than a pH of 4.5. 13.The method of claim 12, wherein said acidic pH is from about 2 to about4.
 14. The method of claim 12, wherein said acidic pH is about
 3. 15.The method of claim 12, wherein said acidic pH is about 3.5
 16. Themethod of claim 12, wherein said combination further comprises acrystallization inhibitor.
 17. The method of claim 12, wherein saidcombination is in the form of a solution.
 18. The method of claim 12,wherein said combination is in the form of a spray solution.
 19. Themethod of claim 12, wherein said permeation enhancer is a Hsiehenhancer.
 20. The method of claim 19, wherein said Hsieh enhancer iscyclopentadecalactone or cylcohexadecanone.
 21. The method of claim 12,wherein said permeation enhancer is a straight chain or branchedcompound of the saturated or unsaturated aliphatic type.
 22. The methodof claim 21, wherein said straight chain or branched compound of thesaturated or unsaturated aliphatic type is selected from the groupconsisting of: myristyl myristate, isopropyl myristate, octyl palmitate,and ethyl oleate.